On 2019/11/5 5:52 下午, Paul Menzel wrote: > Dear Coly, > > > Thank you for improving the documentation. > > On 2019-11-05 08:55, Coly Li wrote: >> When growing a raid0 device, if the new component disk size is not >> big enough, the grow operation may fail due to lack of backup space. >> >> The minimum backup space should be larger than >> LCM(old, new) * chunk-size * 2 >> Here LCM stands for Least Common Multiple calculation, old and new >> are devices number before and after the grow operation, "* 2" comes > > device numbers Copied. I am not sure whether it should be "device numbers" or maybe "devices numbers", this confuses me *^_^* > >> from the fact that mdadm refuses to use more than half of a spare >> device for backup space. >> >> There are users reported such failure when they grew a raid0 array > > There are users reporting … > >> with small component disk. Neil Brown points out this is not a bug >> and how the failure comes. This patch adds note information into >> mdadm(8) man page in the Notes part of GROW MODE section, to explain > > Comma can be removed. Without the comma, I feel the sentence is too long to have a breath for readers LOL.. > >> a minimum size requirement of new component disk size or external > > s/a/the/ Copied, I will update this in next version. > >> backup size. >> >> Signed-off-by: Coly Li <colyli@xxxxxxx> >> Cc: NeilBrown <neilb@xxxxxxx> >> --- >> mdadm.8.in | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/mdadm.8.in b/mdadm.8.in >> index 9aec9f4..dfb55e3 100644 >> --- a/mdadm.8.in >> +++ b/mdadm.8.in >> @@ -2727,6 +2727,14 @@ option and it is transparent for assembly feature. >> .IP \(bu 4 >> Roaming between Windows(R) and Linux systems for IMSM metadata is not >> supported during grow process. >> +.IP \(bu 4 >> +When growing a raid0 device, the new component disk size (or external >> +backup size) should be larger than LCM(old, new) * chunk-size * 2. Here >> +LCM stands for Least Common Multiple calculation, old and new are >> +devices number before and after the grow operation, "* 2" comes from > > device numbers > > Note, that I am not a native speaker. Neither me :-) Thanks for the review, I will wait for comments from Neil and Jes, then post an update version. -- Coly Li
